WO2008022850A1 - procÉdÉ et agencement pour la mesure optique du profil superficiel d'objets - Google Patents

procÉdÉ et agencement pour la mesure optique du profil superficiel d'objets Download PDF

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Publication number
WO2008022850A1
WO2008022850A1 PCT/EP2007/057243 EP2007057243W WO2008022850A1 WO 2008022850 A1 WO2008022850 A1 WO 2008022850A1 EP 2007057243 W EP2007057243 W EP 2007057243W WO 2008022850 A1 WO2008022850 A1 WO 2008022850A1
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WO
WIPO (PCT)
Prior art keywords
particles
camera
light
arrangement
sensors
Prior art date
Application number
PCT/EP2007/057243
Other languages
German (de)
English (en)
Inventor
Lucius Remer
Volker Seyfried
Original Assignee
Leica Microsystems Cms Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Leica Microsystems Cms Gmbh filed Critical Leica Microsystems Cms Gmbh
Priority to EP07787511A priority Critical patent/EP2073751A1/fr
Publication of WO2008022850A1 publication Critical patent/WO2008022850A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
    • A61B5/1077—Measuring of profiles
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
    • A61B5/4538—Evaluating a particular part of the muscoloskeletal system or a particular medical condition
    • A61B5/4542—Evaluating the mouth, e.g. the jaw
    • A61B5/4547—Evaluating teeth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C9/00—Impression cups, i.e. impression trays; Impression methods
    • A61C9/004—Means or methods for taking digitized impressions
    • A61C9/0046—Data acquisition means or methods
    • A61C9/0053—Optical means or methods, e.g. scanning the teeth by a laser or light beam

Definitions

  • the invention relates to a method and an arrangement for the optical measurement of the surface profile of objects, in particular of teeth, rows of teeth or tooth stumps.
  • phase map can first be determined, which is then converted into the topography by the so-called phase unwrapping. Under this condition, the pixel coordinates of a stripe image on a CCD camera chip can be converted into the corresponding object coordinates.
  • the fact that the tooth material is translucent has a disadvantageous effect. Due to the translucency, the striped pattern projected onto the surface of the tooth partially penetrates the tooth. In addition, the penetration depth may also depend on the surface condition of the tooth material. The penetration of the stripe pattern into the tooth interior falsifies the image of the surface structure of the tooth, which results in a significant deterioration of the measurement result. To circumvent this problem, it has been proposed to apply to the surface a layer of matting contrast powder or a layer of fluorescent liquid. Although these measures solve the problem that the projected fringe pattern partially penetrates into the tooth.
  • the present invention is based on the object, a
  • the above object is achieved with regard to a method having the features of patent claim 1.
  • the inventive method is characterized in that a structure is applied to the surface of the object, wherein the structure composed of individual, distributed on the surface of the object measuring points, that the object is illuminated by a light source and that emanating from the applied structure Detection light detected by a camera at different observation angles and from the camera image data, the surface profile of the object is calculated.
  • the arrangement according to the invention is characterized by a device for applying a structure of individual, distributed on the surface of the object measuring points, a light source for illuminating the object, a camera for detecting the emanating from the applied structure detection light at different observation angles and an evaluation unit for calculation the surface profile of the object from the camera image data.
  • interpolation points define measuring points in such a way that the light emanating from the structure when the object is illuminated is detected as detection light by means of a camera. Specifically, the detection light emanating from the applied structure is detected at different observation angles and the surface profile of the object is calculated from the camera image data.
  • the method and the arrangement according to the invention operate with high accuracy, since the surface of the object can be measured directly on the basis of the structure applied in physical form to the object.
  • the structure used is a dot structure which is produced by applying individual particles to the surface of the object.
  • Structure reflected and / or scattered and / or polarized light can be detected.
  • the applied particles virtually act as individual scattered light centers.
  • the fluorescence and / or phosphorescence light emanating from the structure as a result of the illumination is detected as detection light.
  • the particles are preferably dissolved in alcohol, since this evaporates rapidly after application.
  • a particularly pleasant application for a patient can be achieved in that the particles, for example, by a (mouth) rinse or as
  • Tincture or by means of a film or a foil. Especially at the
  • the particles are preferably by means of a
  • Chewing gums applied In view of easy removability after completion of the measurement, the particles are advantageously applied in a washable, rinsable and / or peelable form.
  • nanoparticles whose size is less than or equal to 1 ⁇ m. Nanoparticles prove to be particularly advantageous insofar as their size is smaller than the optical resolution.
  • the disadvantage is that nanoparticles can penetrate cells and have a toxic effect.
  • particles having a size in a range between 1 ⁇ m and preferably 200 ⁇ m are advantageously used.
  • they are not toxic, on the other hand they provide more detection light than nanoparticles in view of their larger area, their diameter still being smaller than the optical resolution.
  • the particles can be provided that they are made of metal, which would result in a particularly good reflection of the illumination light from the particles.
  • Beads or with so-called “quantum dots” labeled particles are used.
  • Quantum dots are nanoscopic structures made of semiconductor materials whose optical properties can be tailored by influencing their shape, their size or the number of their electrons.
  • active particles which emit detection light themselves as a result of irradiation may be fluorophore-labeled particles, fluorescent proteins, for example in the form of bacteria with GFP (Green Fluorescence Proteins) and / or autofluorescent particles, as described, for example, in US Pat. occur in food, act.
  • active particles which emit detection light themselves as a result of irradiation.
  • these may be fluorophore-labeled particles, fluorescent proteins, for example in the form of bacteria with GFP (Green Fluorescence Proteins) and / or autofluorescent particles, as described, for example, in US Pat. occur in food, act.
  • the surface profile of the object is calculated using a triangulation method.
  • the camera comprises two spatially spaced-apart photosensitive sensors or detectors. Each particle on the surface of the object is placed on each of the two sensors, i. double, pictured. The distance between the two sensors can be used as base length in the calculations in the triangulation process.
  • CCD chips, EMCCDs, CMOS sensors, avalanche photodiodes (APDs), MEMS (Micro-Electro-Mechanical System) -based detectors and / or PSDs (Position Sensitive Devices) can be used as photosensitive sensors / detectors.
  • a cross correlation between the two sensors of the camera or the two halves of the one sensor of the camera carried out.
  • a clear identification of the imaged points on the sensors of the camera is possible.
  • an evaluation of the focus size of the pixels of the particles on the sensors proves to be advantageous.
  • the color information can be used to identify the particles.
  • a plurality of images of the object are recorded at respectively different detection angles, wherein the individual images are taken in quick succession, preferably at a video rate (for example 24 images per second).
  • the light source is operated pulsed for illuminating the object.
  • the sensors of the camera can be operated with shuttem.
  • CCD chips as sensors, preferably, frame transfer CCDs are used.
  • the luminescent light can be detected advantageously with two colors.
  • an interference light suppression can be achieved in this way by separating detection light, which results from a possible autofluorescence of the object, from the actual fluorescent light of the particles.
  • an artificial blur is generated for the image recording.
  • This blurring can be realized, for example, by imposing a vibration movement with a small amplitude on the sensors and / or an upstream imaging optics, which can be embodied, for example, as a microlens array.
  • This approach will be particular then applied if it turns out that the images of the particles on the sensor are too small. Due to the oscillatory motion of the pixel increases and by gravity formation can be determined its exact position.
  • the surface structure of the object can also be determined by means of a holographic method.
  • the illumination light is split by means of a beam splitter into a reference beam and into an object beam. Since the temporal and spatial stability of an interference pattern formed by the superposition of the wave fields is a decisive prerequisite for the creation of holograms, a spatial fixation of object and camera is advantageous. In that regard, this method is particularly suitable for measuring teeth outside the oral cavity.
  • the illumination light can be fed in a conventional manner via optical fibers.
  • the device can be designed for application as a spray nozzle.
  • the spray nozzle is arranged on a probe, which is fed by the illumination light source.
  • a probe-like arrangement could be inserted into any kind of body cavity.
  • FIG. 2 is a schematic view of a second embodiment of an inventive arrangement with a camera with a single photosensitive sensor
  • FIG. 3 is a schematic view of an image taken with the sensor of FIG. 2 and FIG
  • FIG. 4 shows a schematic view of a third exemplary embodiment of an arrangement according to the invention for carrying out a holographic method.
  • Fig. 1 shows - schematically - a first embodiment of an inventive arrangement for optical measurement of the surface profile of an object 1, wherein it is in the concrete to the measurement of a tooth 2.
  • the tooth 2 has been prepared by applying a dot-shaped structure to the surface.
  • the punctiform structure consists of individual particles 3, which adhere to the surface of the tooth 2.
  • a dot-shaped structure to the surface.
  • the punctiform structure consists of individual particles 3, which adhere to the surface of the tooth 2.
  • Tooth material form the particles 3 an optical contrast and act in the illumination of the tooth 2 by means of an illumination light source 4 as individual scattered light centers.
  • the light source 4 is preferably designed as a laser, as an LED or as a cold light source. Also, the light of a normal lamp or sunlight can be used to illuminate the object 1. Preferably, illumination in the visible wavelength range between 400 and 800 nm is used.
  • the detection light reflected or scattered by the individual particles 3 first passes through a color filter 5 and is then imaged with lenses 6 on two executed as CCD chips 7 sensors 8 a camera, not shown.
  • the lenses 6 and the CCDs 7 are matched to one another such that the resolution of the optics or of the CCDs 7 is sufficient for the detection of the individual particles 3.
  • the vote is chosen so that the detection light of each particle 3 meets a few pixels of a CCD 7.
  • the viewing angle is changed and the dot structure is recorded again.
  • a video sequence is created by consecutively taking a plurality of images of the object 1 from different directions.
  • hidden areas of the object 1 are also detected during an image acquisition from a certain observation angle.
  • the three-dimensional image of the tooth 2 to be measured is calculated by means of a triangulation method.
  • the distance of the two CCD chips 7 of the camera serves as a base length.
  • FIG. 2 and 3 show a second embodiment of an inventive arrangement, wherein - in contrast to the arrangement of FIG. 1 - the detection light of the individual particles 3 is detected only with a CCD 7.
  • the same reference numerals designate the same components as in FIG. 1.
  • a plurality of exposures of the object 1 are taken from different positions, i. taken at different viewing angles.
  • the recordings are preferably made at a video rate, i. for example, with 24 frames per second, recorded.
  • the relative position of the camera can be determined either from the relative camera position or, similar to the GPS principle, directly from the 3-D position.
  • Position of the individual particles 3 are calculated.
  • Fig. 4 finally shows - also schematically - a third embodiment of an inventive arrangement, wherein the three-dimensional structure of the tooth 2 to be measured is determined there by means of a holographic method.
  • the illumination light beam emitted by an illumination light source 4 designed as a laser 9 first passes through a lens 10 and is then split into two partial beams by means of a beam splitter 11.
  • the one partial beam reference beam 12 is directed via a first deflecting mirror 13 directly onto a photosensitive sensor 8 of a camera.
  • the second partial beam - object beam 14 - is directed via a second deflection mirror 15 to the object 1 to be measured and serves to illuminate the applied to the surface of the object 1 point-like structure.
  • each particle 3 generates Fresnel zone plates on the sensor 8 designed as a CCD 7. Its phase is stored on the CCD 7 by superposition with the reference beam 12.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Public Health (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Dentistry (AREA)
  • Veterinary Medicine (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Medical Informatics (AREA)
  • Biophysics (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Molecular Biology (AREA)
  • Epidemiology (AREA)
  • Optics & Photonics (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Rheumatology (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

Abstract

L'invention concerne un procédé et un agencement pour la mesure optique du profil superficiel d'objets, en particulier de dents, de rangées de dents et de moignons, lesquels procédé et agencement sont caractérisés, en vue de l'atteinte d'une haute précision de mesure avec des moyens simples, en ce qu'une structure est appliquée sur la surface de l'objet (1), la structure se composant de points de mesure individuels distribués sur la surface de l'objet (1), en ce que l'objet (1) est éclairé au moyen d'une source de lumière (4), et en ce que la lumière de détection partant de la structure appliquée est détectée au moyen d'une chambre photographique sous différents angles d'observation, le profil de surface de l'objet (1) étant calculé d'après les données des images de la chambre photographique.
PCT/EP2007/057243 2006-08-25 2007-07-13 procÉdÉ et agencement pour la mesure optique du profil superficiel d'objets WO2008022850A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP07787511A EP2073751A1 (fr) 2006-08-25 2007-07-13 Methode et dispositif de mesure optique de profils de surface d'objets

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006039803A DE102006039803A1 (de) 2006-08-25 2006-08-25 Verfahren und Anordnung zur optischen Vermessung des Oberflächenprofils von Ojekten
DE102006039803.3 2006-08-25

Publications (1)

Publication Number Publication Date
WO2008022850A1 true WO2008022850A1 (fr) 2008-02-28

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PCT/EP2007/057243 WO2008022850A1 (fr) 2006-08-25 2007-07-13 procÉdÉ et agencement pour la mesure optique du profil superficiel d'objets

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EP (1) EP2073751A1 (fr)
DE (1) DE102006039803A1 (fr)
WO (1) WO2008022850A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011056574A1 (fr) * 2009-10-26 2011-05-12 Olaf Andrew Hall-Holt Système d'imagerie dentaire et procédé associé
US8999371B2 (en) 2012-03-19 2015-04-07 Arges Imaging, Inc. Contrast pattern application for three-dimensional imaging

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3541891A1 (de) * 1985-11-27 1987-06-04 Kambiz Kachanian Verfahren zur erfassung, speicherung und wiedergabe von geometrischen daten von objekten, insbesondere von kiefermodellen und eine vorrichtung zur durchfuehrung des verfahrens
DE19506642C1 (de) * 1995-02-25 1996-03-21 Focus Mestechnik Gmbh & Co Kg Verfahren und Vorrichtung zum optischen Ausmessen der Oberflächenkontur eines Werkstückes
WO1997014932A1 (fr) * 1995-10-20 1997-04-24 Optronic Consult Ab Procede et dispositif de mesure d'une forme en trois dimensions
WO1998048242A1 (fr) * 1997-04-18 1998-10-29 Optronic Consult Ab Procede et dispositif de mesure de formes tridimensionnelles
WO2003077839A2 (fr) * 2002-03-14 2003-09-25 Orametrix, Inc. Procede de balayage de champ humide

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3541891A1 (de) * 1985-11-27 1987-06-04 Kambiz Kachanian Verfahren zur erfassung, speicherung und wiedergabe von geometrischen daten von objekten, insbesondere von kiefermodellen und eine vorrichtung zur durchfuehrung des verfahrens
DE19506642C1 (de) * 1995-02-25 1996-03-21 Focus Mestechnik Gmbh & Co Kg Verfahren und Vorrichtung zum optischen Ausmessen der Oberflächenkontur eines Werkstückes
WO1997014932A1 (fr) * 1995-10-20 1997-04-24 Optronic Consult Ab Procede et dispositif de mesure d'une forme en trois dimensions
WO1998048242A1 (fr) * 1997-04-18 1998-10-29 Optronic Consult Ab Procede et dispositif de mesure de formes tridimensionnelles
WO2003077839A2 (fr) * 2002-03-14 2003-09-25 Orametrix, Inc. Procede de balayage de champ humide

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011056574A1 (fr) * 2009-10-26 2011-05-12 Olaf Andrew Hall-Holt Système d'imagerie dentaire et procédé associé
US20110207074A1 (en) * 2009-10-26 2011-08-25 Olaf Andrew Hall-Holt Dental imaging system and method
US8999371B2 (en) 2012-03-19 2015-04-07 Arges Imaging, Inc. Contrast pattern application for three-dimensional imaging
US9561281B2 (en) 2012-03-19 2017-02-07 Arges Imaging, Inc. Contrast pattern application for three-dimensional imaging
US9968524B2 (en) 2012-03-19 2018-05-15 Arges Imaging, Inc. Contrast pattern application for three-dimensional imaging

Also Published As

Publication number Publication date
DE102006039803A1 (de) 2008-03-20
EP2073751A1 (fr) 2009-07-01

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